Model contracts

A Dropbear observation is expressed in the selected model’s coordinates, not necessarily your controller’s coordinates. Convert at the RobotIO boundary and validate the returned model action before converting it back.

Matching a vector length is not enough. Joint order, units, camera order, gripper convention, and absolute-versus-delta semantics must all match.

The production catalog exposes the contracts below. Check Models before opening a session because availability is region- and account-dependent, and some models require an entitlement on your organization.

Model	Observation helper	Output	Nominal rate	Access
`molmoact2-so101`	`dropbear.so101.observe`	30 × 6 absolute joint positions	30 Hz	Open
`molmoact2-libero`	`dropbear.libero.observe`	10 × 7 delta end-effector actions	10 Hz	Open
`molmoact2-droid`	`dropbear.franka.observe`	15 × 8 absolute joint/gripper targets	15 Hz	Open
`dreamzero-yam`	bimanual observation, see below	24 × 14 absolute joint/gripper targets	30 Hz	Entitlement required

molmoact2-droid is listed in the catalog but has no serving capacity in the current region set. dropbear status --model molmoact2-droid reports what is actually available before you write against it.

DreamZero-YAM

DreamZero-YAM drives a bimanual I2RT YAM. It is entitlement-gated: your organization must be granted access before a session will open.

This is a research robot-control model. Validate the task, workspace, joint and velocity limits, emergency stop, and human supervision before any hardware use.

Observation

Three RGB cameras and the packed bimanual joint state, each frame carrying a real monotonic capture time:

observation = dropbear.dreamzero_yam.observe(
    top_frame=top_rgb,
    left_frame=left_rgb,
    right_frame=right_rgb,
    camera_capture_times_ns=(top_ns, left_ns, right_ns),
    left_joint_positions=left_six_joint_radians,
    left_gripper=left_gripper_position,
    right_joint_positions=right_six_joint_radians,
    right_gripper=right_gripper_position,
)

Action

Property	Value
Shape	24 × 14
Space	`raw_absolute_joint`
Ordering	left six joints, left gripper, right six joints, right gripper
Gripper indices	6 and 13
Native rate	30 Hz
Horizon	0.8 s per chunk
Hold behaviour	holds current position when the buffer underruns

Grippers are continuous absolute joint positions, not binary open/close commands. Do not threshold them.

Command rate

The model is native at 30 Hz. You may request 5–30 Hz at connect, and Dropbear stretches the action horizon to match rather than dropping actions, so a 24-step chunk covers 0.8 s at 30 Hz and 2.4 s at 10 Hz. Lower rates trade responsiveness for a longer buffer.

MolmoAct2 SO-101

Observation

observation = dropbear.so101.observe(
    side_frame=side_rgb,
    wrist_frame=wrist_rgb,
    joint_positions=[
        shoulder_pan_deg,
        shoulder_lift_deg,
        elbow_flex_deg,
        wrist_flex_deg,
        wrist_roll_deg,
        gripper_position,
    ],
)

side_frame: H×W×3 RGB image.
wrist_frame: H×W×3 RGB image from a distinct arm-mounted camera.
joint_positions: six finite values in LeRobot SO-101 order and degrees.
gripper_position: LeRobot’s 0–100 position convention.
actions_remaining: optional nonnegative buffer depth; the policy loop sets this when needed.

Action

Each returned action has this order:

[shoulder_pan, shoulder_lift, elbow_flex, wrist_flex, wrist_roll, gripper]

The values are absolute targets in the same degrees and gripper convention as the observation. A normal chunk contains 30 actions for a 30 Hz controller. On an underrun, the managed loop uses the current observation position as its hold target. Your robot controller must still enforce per-tick changes, motor limits, watchdogs, and the physical stop path.

MolmoAct2 LIBERO

Observation

observation = dropbear.libero.observe(
    agent_frame=agent_rgb,
    wrist_frame=wrist_rgb,
    state=[
        eef_x,
        eef_y,
        eef_z,
        axis_angle_x,
        axis_angle_y,
        axis_angle_z,
        gripper_qpos_0,
        gripper_qpos_1,
    ],
)

The eight state values are end-effector position, end-effector rotation as an axis-angle vector converted from the environment’s XYZW quaternion, then the two simulator gripper joint positions.

Action

A normal chunk contains ten 7D robosuite/LIBERO delta actions at 10 Hz:

[delta_x, delta_y, delta_z, delta_axis_x, delta_axis_y, delta_axis_z, gripper]

Use the action directly only with the matching LIBERO/robosuite environment configuration. A physical robot controller has a different contract.

MolmoAct2 DROID

Observation

observation = dropbear.franka.observe(
    exterior_frame=exterior_rgb,
    wrist_frame=wrist_rgb,
    joint_positions=joint_radians,
    gripper=gripper_position,
    second_exterior_frame=second_exterior_rgb,
)

exterior_frame: required H×W×3 uint8 RGB view.
wrist_frame: required H×W×3 uint8 RGB view.
second_exterior_frame: optional second exterior RGB view. When omitted, Dropbear maps the first exterior view to both exterior inputs.
joint_positions: seven finite Franka joint positions in radians.
gripper: one finite value from 0 (open) to 1 (closed).

Action

Each returned action has this order:

[joint_0, joint_1, joint_2, joint_3, joint_4, joint_5, joint_6, gripper]

The values are absolute joint targets in radians followed by the unit-interval gripper target. A normal chunk contains 15 actions for a 15 Hz controller.

Dropbear provides DROID inference, not a Franka safety controller. Stop at predict() until your local stack validates joint, velocity, acceleration, workspace, collision, gripper, watchdog, and e-stop behavior.

Validate at the boundary

For every model:

Record the raw controller state and the converted model state.
Assert camera color order, dtype, shape, and source identity.
Assert vector length, order, units, and finite values.
Inspect one non-actuating prediction.
Reject every output outside local limits before any coordinate conversion.
Test hold and e-stop behavior without cloud connectivity.

Continue to the SO-101 or Franka recipe.

Getting started

Build with Python

Robot guides

Reference

Help

DreamZero-YAM

Observation

Action

Command rate

MolmoAct2 SO-101

Observation

Action

MolmoAct2 LIBERO

Observation

Action

MolmoAct2 DROID

Observation

Action

Validate at the boundary

​DreamZero-YAM

​Observation

​Action

​Command rate

​MolmoAct2 SO-101

​Observation

​Action

​MolmoAct2 LIBERO

​Observation

​Action

​MolmoAct2 DROID

​Observation

​Action

​Validate at the boundary

DreamZero-YAM

Observation

Action

Command rate

MolmoAct2 SO-101

Observation

Action

MolmoAct2 LIBERO

Observation

Action

MolmoAct2 DROID

Observation

Action

Validate at the boundary